feat: Implement Free Issue functionality in Shop PO and Invoice management

distribution_fe/app/(dashboard)/sales/new/page.tsx

@@ -29,6 +29,7 @@ import {
   getPaginatedItems,
 } from '@/lib/api/index'
 import type { ItemSummaryResponse, StoreResponse, UserResponse } from '@/types/api'
+import { FreeIssuePanel, type FreeLine } from '../_components/free-issue-panel'
 
 const lineItemSchema = z.object({
   itemId: z.string().min(1, 'Item is required'),
@@ -57,6 +58,8 @@ export default function NewShopPOPage() {
   const [usersList, setUsersList] = useState<UserResponse[]>([])
   const [priceMinByIndex, setPriceMinByIndex] = useState<Record<number, number | null>>({})
   const [priceRetailByIndex, setPriceRetailByIndex] = useState<Record<number, number | null>>({})
+  const [freeLines, setFreeLines] = useState<FreeLine[]>([])
+  const [discountIds, setDiscountIds] = useState<string[]>([])
 
   const form = useForm<FormValues>({
     resolver: zodResolver(schema),
@@ -125,9 +128,13 @@ export default function NewShopPOPage() {
   async function onSubmit(values: FormValues) {
     try {
       await shopPosApi.create({
+        discountSchemeIds: discountIds,
         storeId: values.storeId,
         raisedByUserId: values.raisedByUserId,
-        items: values.items,
+        items: [
+          ...values.items,
+          ...freeLines.map((l) => ({ itemId: l.itemId, quantity: l.quantity, isFree: true, schemeId: l.schemeId })),
+        ],
       })
       toast.add({ title: 'Shop PO created', type: 'success' })
       router.push('/sales')
@@ -343,6 +350,19 @@ export default function NewShopPOPage() {
           </div>
         </div>
 
+        <FreeIssuePanel
+          storeId={watchedStoreId}
+          paidLines={watchedItems.map((l) => ({
+            itemId: l.itemId,
+            quantity: Number(l.quantity) || 0,
+            unitPrice: Number(l.unitPrice) || 0,
+          }))}
+          freeLines={freeLines}
+          onChange={setFreeLines}
+          discountIds={discountIds}
+          onDiscountChange={setDiscountIds}
+        />
+
         <div className="flex justify-end">
           <div className="w-full rounded-2xl border p-6 sm:w-96">
             <h3 className="text-sm font-medium text-foreground">Order Summary</h3>